As is well known, liquid crystal devices do not themselves emit light; instead, they produce displays or the like simply by changing the paths of light. Therefore, all liquid crystal devices necessarily have some type of arrangement for directing light into panels. In view of this, liquid crystal devices are far different from other display devices, such as electroluminescent displays and plasma displays. A liquid crystal device in which light incident from a light source or the like disposed at a rear side of a panel is emitted to an observing side after passing through the panel is called a transmissive type, and a liquid crystal device in which ambient light incident from an observing side is emitted to an observing side by reflection by a panel, is called a reflective type.
In reflective type devices, the amount of ambient light incident from the observing side is not large compared to light incident from a light source disposed at a rear side of a panel. In addition, reflective type devices have high attenuation of light in each part thereof because, when the light is reflected, the light retraces its path through the panel, so that light emitted to an observing side is less than that in transmissive types. Accordingly, reflective type devices have a problem that display screens thereof are generally darker compared to transmissive type devices.
On the other hand, reflective type devices have advantages such as being able to produce a display without a light source, which consumes large amount of electric power, being highly visible outdoors even in bright light, and the like. Hence, in some cases, the above advantages of reflective type devices overcome problems therein. Consequently, there is an increasing demand for reflective type liquid crystal devices for portable electronic apparatuses; however, a substantial problem remains in that when there is practically no ambient light, users cannot see the display of reflective type devices. A so-called “transflective liquid crystal device” is proposed as one solution to overcome this problem. In a bright environment, the liquid crystal device mainly uses reflection of ambient light, similar to that used in ordinary reflective type devices. However, in a dark environment, the transmissive type device is additionally used by lighting a light source disposed on a rear side of a panel, and therefore the device display can be seen in either situation. Moreover, concomitant with a recent demand for color displays for portable electronic devices, office automation apparatuses, and the like, color displays in transflective type liquid crystal devices are required in many cases.
A transflective liquid crystal device capable of providing a color display is described in, for example, Japan Unexamined Patent Application Publication No. 7-318919. The liquid crystal device which is disclosed in the above unexamined patent application, is provided inside a liquid crystal layer with pixel electrodes which also serve as a transflective film and has an arrangement for producing a color display. In the above arrangement, a color display is produced by coloring light by birefringent effects of a liquid crystal layer and a retardation film, and by polarization effects of polarizers provided at an observing side and at a rear side of a liquid crystal panel. Since the transflective film is provided inside the liquid crystal layer in the arrangement described above, double images, blurred display, and the like caused by parallax are avoided, and superior bright colored light can be obtained compared to an arrangement having a transflective film outside a liquid crystal layer.